What is oscillatory motion ?

Answer

### Step-by-Step Solution:

1. **Definition of Oscillatory Motion**:
Oscillatory motion refers to the repetitive back-and-forth movement of a particle around a fixed point. This fixed point is known as the mean position.

2. **Characteristics of Oscillatory Motion**:
- The motion is periodic, meaning it repeats itself after a certain interval of time.
- The particle moves to a maximum displacement on one side (known as the extreme position) and then returns to the mean position, moving to the maximum displacement on the opposite side.

3. **Mean Position**:
The mean position is the central point around which the oscillation occurs. It is the position where the net force acting on the particle is zero.

4. **To and Fro Motion**:
The term "to and fro motion" describes the movement of the particle as it travels from the mean position to one extreme position and back to the mean position, then to the opposite extreme position, and back again.

5. **Continuous Nature of Oscillatory Motion**:
This motion continues indefinitely as long as there are no external forces acting on the particle that would stop or alter its motion.

### Final Definition:
In summary, oscillatory motion is the to-and-fro movement of a particle around a fixed point (mean position), characterized by periodicity and continuous repetition of motion between two extreme positions.

---